The present invention relates to a windshield cleaning device for motor vehicles which, under consideration of the ambient temperature, provides for the best possible clear view through the windshield.
It is already known to provide the cleaning liquid for cleaning the windshield with surface-active substances, in order to be able to remove soot, grease, lubricants, and, optionally also dust and salt from the windshield. The use of a water-based cleaning liquid at low, especially negative, ambient temperatures (Celsius scale) is possible by employing mixtures with alcohol whereby the alcohol/water composition must be matched to the expected ambient temperature. Since the ambient temperature, however, changes during the course of the day, in general, to a more positive temperature value, while, on the other hand, the wind chill from driving causes on the windshield a temperature drop, the composition with respect to the amount of alcohol must be such that, in the least favorable case, freezing of the cleaning liquid on the windshield and especially in the spray nozzles is safely prevented.
For a fast removal of snow and ice from the windshield of a vehicle that is parked outdoors, especially after an unpredicted snowstorm or temperature drop, it is favorable when heated cleaning liquid can be used. For this purpose, it is known to use electrical heating elements that are operated, in general, by electric energy taken from the motor vehicle battery. Another possibility for heating the cleaning liquid is the use of a heat exchanger which will heat the cleaning liquid with the aid of the hot cooling water circulating in the running engine so that the relatively low amount of energy stored in the battery can be saved.
With the aforementioned measures, it is possible within a certain amount of time to provide a clean windshield and thus a clear view. However, the expenditure with regard to the cleaning liquid and in the cold seasons of the year also with regard to the added alcohol mixture, are considerable.
It is therefore an object of the present invention to provide a windshield cleaning device with which the amount of cleaning liquid as well as the required amount of alcohol or alcohol mixture (commercial windshield wiper liquids contain a water/alcohol mixture) can be considerably reduced without having a detrimental effect with regard to the quality of the cleaning action.